Inlay

Bacillus populations restore amino acid metabolism in Mesorhizobium under saline–alkali stress to enhance nitrogen fixation efficiency | The ISME Journal | Oxford Academic

Xylem Endophytes of Salicaceae: potential role in mitigating disease symptoms from Xylella fastidiosa or Brenneria salicis 📖 nph.onlinelibrary.wiley.com/doi/10.1111/... by Pesenti et al. @WileyPlantSci #PlantScience

📢 New paper from the lab! "Phytophthora root rot induces compositional and functional changes in avocado rhizosphere bacterial communities" We analyzed through metabarcoding and metatranscriptomic analyses the shifts in the 🥑 microbiota induced by #Phytophthora academic.oup.com/femsmicrobes...

Great paper from @poolelaboxford.bsky.social on the sanctions of rhizobial cheaters and how rhizobia can evade them. -> Resource allocation to pea plant nodules impacted by nitrogen fixation potential of infecting rhizobia

Very clear review on plant iron acquisition in the context of plant-microbe interactions -> Integrating microbial siderophores into concepts of plant iron nutrition

The first article from Elsa Hilaire’s PhD thesis. The first in a long series...??? "Necromass chemistry drives the functional diversity of the necrobiome, resulting in microbe–organic matter feedbacks" besjournals.onlinelibrary.wiley.com/doi/10.1111/...

Very happy to see this lab paper out in @newphyt.bsky.social - we identified genomic traits & environmental drivers of ectomycorrhizal fungal mycelium exploration in the soil and on roots. Thanks to all our co-authors and to @tommansfield.bsky.social doi.org/10.1111/nph....

Similar microbes, different outcomes. Why do some rhizobial bacteroids fix nitrogen in legumes better than others? Check out the online version of our latest work by @poolelaboxford.bsky.social, an historical lab project showing how this comes down to differentiation 😉 ➡️ doi.org/10.1093/plph...

Happy to share our latest work in collaboration with the lab of @pengbo10.bsky.social. Here, we describe that a formin protein mediates the polarity switch from root hair to infection thread growth during symbiotic interactions. www.science.org/doi/10.1126/...

📢 Our article on the avocado #nectar #microbiota is now put in @jxbotany.bsky.social ! 🥑🌸🦠🐝 The microbiota of avocado floral nectar inhibits pathogens and improves plant fitness #microsky #MexicanScience

The root nodules formed by rhizobia and leguminous plants are specialized structures for nitrogen fixation. However, a large number of non-rhizobial endophytes also coexist within the nodules, and their contribution to nitrogen fixation under abiotic stress conditions remains unclear. Here, using the wild leguminous shrub Sophora davidii as model system, we identified an important NRE (Bacillus siamensis BT-9-1) by analyzing keystone taxa within the bacterial cooccurrence network of root nodules. This strain could improve the survival of Mesorhizobium metallidurans YC-39 under saline–alkali stress. A mechanistic investigation revealed that the expression of ilvA, ilvH, and ilvD was downregulated, and the contents of (2S)-isopropylmalate and succinic acid decreased in M. metallidurans YC-39 under saline–alkali conditions, whereas B. siamensis BT-9-1 presented increased accumulation of these metabolites. These findings indicate that B. siamensis BT-9-1 cross-feeds M. metallidurans YC-39 with these metabolites, rescuing the compromised branched-chain amino acid synthesis pathway and the tricarboxylic acid cycle in saline–alkali environments. Eventually, coinoculation with B. siamensis BT-9-1 and M. metallidurans YC-39, along with (2S)-isopropylmalate and succinic acid supplementation, increased nitrogenase activity of the symbionts. Our study reveals a novel mechanism by which non-rhizobial endophyte Bacillus species enhances the growth and nitrogen fixation efficiency of M. metallidurans under saline–alkali stress through the delivery of key metabolites.

Compositional and functional readjustments of the rhizobacterial community in avocado induced by Phytophthora root rot.

Legumes host nitrogen-fixing bacteria, called rhizobia, within specialised root structures called nodules, where carbon from the plant is exchanged for ammonia fixed from N2 by the bacteria. Legumes can host multiple bacterial strains at the same time, that vary in their fixation effectiveness, but legumes sanction nodules containing less effectively fixing strains by reducing the provision of nutrients. Understanding how sanctions are applied by plants and how bacteria may try to avoid them is important for understanding the stability of legume-rhizobial symbioses. Using near isogenic Rhizobium leguminosarum strains, on pea, we demonstrate that sanctions are sensitive to the proportion of nodules occupied by a less effective strain and by using split roots show that sanctions are applied based on a global comparison of nodules across the plant’s root system. By using several rhizobia with different levels of fixation, but all derived from the same parent, we show that pea plants can differentiate between bacteria with relatively small variations in fixation effectiveness. We demonstrate that peas integrate global signals to determine whether individual nodules are sanctioned. At the same time these results show that poorly fixing strains can avoid sanctions if they dominate nodulation.

Iron is a crucial micronutrient for plants, but its availability in soil is often limited. Iron deficiency compromises plant growth, and low iron content in crops contributes substantially to the ‘hidden hunger’ that affects human health globally. The elucidation of Strategy I (reduction-based) and Strategy II (phytosiderophore-based) for iron acquisition was a milestone in plant biology and enabled the development of biofortification concepts. However, recent genetic evidence reveals that the boundary between the two strategies is blurred, with many plants possessing elements of both. Here we show that plant iron uptake mechanisms are more complex and diverse than the classical dichotomy suggests. We review evidence for this integrative view and highlight the critical role of microbial siderophores. We explain how plants access iron from microbial siderophores not only indirectly through Strategy I and II pathways but also via the direct uptake of iron–siderophore complexes, an overlooked mechanism that we introduce as Strategy III. We propose three potential routes for this direct uptake and conclude that harnessing Strategy III holds great potential for novel agricultural interventions to enhance iron biofortification and improve human health.

Read the free Plain Language Summary for this article on the Journal blog.

besjournals.onlinelibrary.wiley.com

Ectomycorrhizal fungi (EMF) produce mycelia with variable extension and complexity, which can be classified according to soil ‘exploration types’ (ETs). ETs have received attention as one of the few.....

The higher symbiotic efficiency of pea bacteroids arises from their greater packing density and proteomic bias toward nitrogenase and dicarboxylate metabol

Colonization of plant roots by symbionts requires substantial morphodynamic reorganization. Examples are actin-scaffolded microcompartments called infection pockets formed during root nodule symbiosis...

The floral nectar in avocado hosts microbes with anti-pathogenic activity and probiotic properties in a model plant species.